clean up the websocket Dial code to correctly restart

Signed-off-by: Jeff Carr <jcarr@wit.com>

gorilla.go

@@ -4,7 +4,7 @@
 
 package main
 
-import "flag"
+// import "flag"
 import "log"
 import "net/url"
 import "os"
@@ -18,8 +18,7 @@ import pb "git.wit.com/wit/witProtobuf"
 
 var gorillaConn *websocket.Conn
 
-func readGorillaConn(done chan struct{}, conn *websocket.Conn) {
-	defer close(done)
+func readGorillaConn(conn *websocket.Conn) {
 	for {
 		mytype, message, err := conn.ReadMessage()
 		if err != nil {
@@ -46,7 +45,6 @@ func gorillaSendProtobuf() {
 	if (gorillaConn == nil) {
 		log.Println("gorillaSendProtobuf() gorillaConn == nil")
 		log.Println("Need to re-open connection here")
-		// go gorillaDial()
 		return
 	}
 	msg := pb.CreateSampleEvent()
@@ -60,30 +58,62 @@ func gorillaSendProtobuf() {
 	}
 }
 
-func gorillaDial() {
-	var addr = flag.String("addr", "v000185.testing.com.customers.wprod.wit.com:9000", "http service address")
+func closeGorillaConn() {
+	if gorillaConn == nil {
+		log.Println("gorillaConn already was nil")
+		return
+	}
+
+	// Cleanly close the connection by sending a close message and then
+	// waiting (with timeout) for the server to close the connection.
+	err := gorillaConn.WriteMessage(websocket.CloseMessage, websocket.FormatCloseMessage(websocket.CloseNormalClosure, ""))
+	if err != nil {
+		log.Println("write close:", err)
+		return
+	}
+
+	// this must be called or set to be called with defer
+	gorillaConn.Close()
+	gorillaConn = nil
+}
+
+func gorillaDial(hostname string) {
+	// var addr = flag.String("addr", "v000185.testing.com.customers.wprod.wit.com:9000", "http service address")
+
+	for {
+		// u := url.URL{Scheme: "ws", Host: *addr, Path: "/event"}
+		u := url.URL{Scheme: "ws", Host: hostname, Path: "/event"}
+		log.Printf("connecting to %s", u.String())
+
+		conn, _, err := websocket.DefaultDialer.Dial(u.String(), nil)
+		if err != nil {
+			log.Println("gorilla Dial failed", err)
+		} else {
+			gorillaConn = conn
+
+			// handle inbound messages on the channel
+			readGorillaConn(conn)
+			closeGorillaConn()
+		}
+
+		time.Sleep(time.Second * 5) // try every 5 seconds
+	}
+}
+
+//
+// this is a facinating code snippet that I wanted to leave here because it is
+// so interesting. Complements to the gorilla websocket example developers
+//
+func beautifulAndFacinatingChannel() {
+	done := make(chan struct{})
 
 	interrupt := make(chan os.Signal, 1)
 	signal.Notify(interrupt, os.Interrupt)
 
-	u := url.URL{Scheme: "ws", Host: *addr, Path: "/event"}
-	log.Printf("connecting to %s", u.String())
-
-	conn, _, err := websocket.DefaultDialer.Dial(u.String(), nil)
-	if err != nil {
-		log.Println("gorilla Dial failed", err)
-		return
-	}
-	defer conn.Close()
-	gorillaConn = conn
-
-	done := make(chan struct{})
-
-	// handle inbound messages on the channel
-	go readGorillaConn(done, conn)
-
 	ticker := time.NewTicker(time.Second * 1)
+
 	defer ticker.Stop()
+	defer close(done)
 
 	for {
 		select {
@@ -94,13 +124,9 @@ func gorillaDial() {
 		case <-interrupt:
 			log.Println("interrupt")
 
-			// Cleanly close the connection by sending a close message and then
-			// waiting (with timeout) for the server to close the connection.
-			err := conn.WriteMessage(websocket.CloseMessage, websocket.FormatCloseMessage(websocket.CloseNormalClosure, ""))
-			if err != nil {
-				log.Println("write close:", err)
-				return
-			}
+			gorillaSendProtobuf()
+
+			// not sure what this does. nothing right?
 			select {
 			case <-done:
 			case <-time.After(time.Second):

main.go

@@ -27,6 +27,9 @@ import _ "github.com/andlabs/ui/winmanifest"
 // always sorted slice (new project)
 // https://github.com/yaa110/sslice
 
+// several smart slice functions (new project. April 2019)
+// https://github.com/elliotchance/pie
+
 // Exit and write out the config
 // (in yaml and json I guess.)
 // switch to json once it can be made human readable
@@ -62,8 +65,7 @@ func main() {
 	// setups up a dnssecsocket()
 	go retrySocket()
 
-	time.Sleep(3 * 1000 * 1000 * 1000)
-	go gorillaDial()
+	go gorillaDial("v000185.testing.com.customers.wprod.wit.com:9000")
 
 	// make this the main loop in an attempt to figure out the crashes
 	// do not change this until the GUI is stable